triedb/pathdb: improve history indexer

triedb/pathdb/history_indexer.go

@@ -455,6 +455,61 @@ func (i *indexIniter) readBlockTime(historyID uint64) (uint64, error) {
 	return header.Time, nil
 }
 
+const (
+	// syncHistoryThreshold is the time window behind the chain head.
+	// If the block being indexed is within this window, we consider the node
+	// to be close enough to the tip to operate in real-time mode.
+	syncHistoryThreshold = 6 * time.Hour
+
+	// indexerIdleTimeout is the maximum duration of inactivity allowed
+	// before the indexer decides it has finished its current catch-up
+	// and exits the initial sync mode.
+	indexerIdleTimeout = 30 * time.Second
+
+	// indexerHeartbeatInterval is the frequency at which the indexer
+	// checks its status and schedules background indexing operations.
+	//
+	// It is a deliberate design choice to introduce this delay instead
+	// of scheduling tasks immediately; this forces the indexer into
+	// "batch index mode" which significantly improves database I/O
+	// efficiency and reduces overhead.
+	indexerHeartbeatInterval = 15 * time.Second
+)
+
+// checkExit reports whether the initial mode has completed. It assumes that
+// all local histories have been fully indexed when invoked, and determines
+// whether the initial mode should exit and marking historical state access
+// as available.
+func (i *indexIniter) checkExit(lastEventTime time.Time) bool {
+	// Verify that the timestamp of the most recently indexed history
+	// is sufficiently close to the current time, ensuring that the
+	// majority of histories have been indexed in batch.
+	timestamp, err := i.readBlockTime(i.indexed.Load())
+	if err != nil {
+		i.log.Warn("Failed to read block time", "err", err)
+		return false
+	}
+	blockTime := time.Unix(int64(timestamp), 0)
+
+	// By default, 128 layers are piled up, which corresponds to roughly 25 minutes
+	// with Ethereum's block interval (12s). A threshold of 6 hours is chosen as a
+	// conservative and safe default for whatever reason.
+	if time.Since(blockTime) < syncHistoryThreshold {
+		i.log.Info("Exit the initial mode as close to chain tip", "last", i.indexed.Load(), "age", common.PrettyAge(blockTime))
+		return true
+	}
+	// The most recently indexed block is still at least 6 hours behind. The node
+	// may be syncing toward a historical block rather than the latest chain head.
+	// In this case, check whether the indexer has been idle for a while and exit
+	// the initial mode if so.
+	if time.Since(lastEventTime) > indexerIdleTimeout {
+		i.log.Info("Exit the initial mode due to inactivity", "last", i.indexed.Load(), "age", common.PrettyAge(blockTime))
+		return true
+	}
+	i.log.Debug("Histories fully indexed, waiting next wave", "last", i.indexed.Load(), "age", common.PrettyAge(blockTime))
+	return false
+}
+
 func (i *indexIniter) run(lastID uint64, recover bool) {
 	defer i.wg.Done()
 
@@ -463,13 +518,12 @@ func (i *indexIniter) run(lastID uint64, recover bool) {
 		done      chan struct{}
 		interrupt *atomic.Int32
 
-		start         = time.Now()
-		lastCheckTime time.Time
-
 		// checkDone reports whether indexing has completed for all histories.
 		checkDone = func() bool {
 			return i.indexed.Load() == lastID
 		}
+		lastEventTime = time.Now()
+		heartBeat     = time.NewTicker(indexerHeartbeatInterval)
 	)
 	if recover {
 		var aborted bool
@@ -479,12 +533,10 @@ func (i *indexIniter) run(lastID uint64, recover bool) {
 		}
 	}
 	for {
-		if done == nil && !checkDone() {
-			done, interrupt = make(chan struct{}), new(atomic.Int32)
-			go i.index(done, interrupt, lastID)
-		}
 		select {
 		case signal := <-i.interrupt:
+			lastEventTime = time.Now()
+
 			// The indexing limit can only be extended or shortened continuously.
 			newLastID := signal.newLastID
 			if newLastID != lastID+1 && newLastID != lastID-1 {
@@ -529,40 +581,34 @@ func (i *indexIniter) run(lastID uint64, recover bool) {
 		case <-done:
 			done, interrupt = nil, nil
 
-			if checkDone() && time.Since(lastCheckTime) > time.Second*8 {
-				lastCheckTime = time.Now()
-
-				// Verify that the timestamp of the most recently indexed history
-				// is sufficiently close to the current time, ensuring that the
-				// majority of histories have been indexed in batch.
-				timestamp, err := i.readBlockTime(lastID)
-				if err != nil {
-					i.log.Warn("Failed to read block time", "err", err)
-					continue
-				}
-				blockTime := time.Unix(int64(timestamp), 0)
-
-				// By default, 128 layers are piled up, which corresponds to roughly 25 minutes
-				// with Ethereum's block interval (12s). A threshold of 6 hours is chosen as a
-				// conservative and safe default for whatever reason.
-				if time.Since(blockTime) > 6*time.Hour {
-					i.log.Debug("Histories fully indexed, waiting next wave", "age", common.PrettyAge(blockTime))
-					continue
-				}
+			if i.checkExit(lastEventTime) {
 				close(i.done)
-				i.log.Info("Histories have been fully indexed", "last", lastID, "age", common.PrettyAge(blockTime), "elapsed", common.PrettyDuration(time.Since(start)))
 				return
 			}
 
+		case <-heartBeat.C:
+			if done != nil {
+				continue
+			}
+			if checkDone() {
+				if i.checkExit(lastEventTime) {
+					close(i.done)
+					return
+				}
+				continue
+			}
+			// Any pending tasks are scheduled for background execution, driven by the
+			// heartbeat ticker. This interval ensures that historical data is processed
+			// in batches rather than individually.
+			done, interrupt = make(chan struct{}), new(atomic.Int32)
+			go i.index(done, interrupt, lastID)
+
 		case <-i.closed:
 			if done != nil {
 				interrupt.Store(1)
 				i.log.Info("Waiting background history index initer to exit")
 				<-done
 			}
-			if checkDone() {
-				close(i.done)
-			}
 			return
 		}
 	}